{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-37756", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:23.938Z", "datePublished": "2025-05-01T12:56:00.539Z", "dateUpdated": "2026-08-05T11:57:19.159Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:57:19.159Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: tls: explicitly disallow disconnect\n\nsyzbot discovered that it can disconnect a TLS socket and then\nrun into all sort of unexpected corner cases. I have a vague\nrecollection of Eric pointing this out to us a long time ago.\nSupporting disconnect is really hard, for one thing if offload\nis enabled we'd need to wait for all packets to be _acked_.\nDisconnect is not commonly used, disallow it.\n\nThe immediate problem syzbot run into is the warning in the strp,\nbut that's just the easiest bug to trigger:\n\n WARNING: CPU: 0 PID: 5834 at net/tls/tls_strp.c:486 tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486\n RIP: 0010:tls_strp_msg_load+0x72e/0xa80 net/tls/tls_strp.c:486\n Call Trace:\n \n tls_rx_rec_wait+0x280/0xa60 net/tls/tls_sw.c:1363\n tls_sw_recvmsg+0x85c/0x1c30 net/tls/tls_sw.c:2043\n inet6_recvmsg+0x2c9/0x730 net/ipv6/af_inet6.c:678\n sock_recvmsg_nosec net/socket.c:1023 [inline]\n sock_recvmsg+0x109/0x280 net/socket.c:1045\n __sys_recvfrom+0x202/0x380 net/socket.c:2237" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is triggered by the socket owner issuing `connect(fd, AF_UNSPEC)` followed by `recvmsg()` on their own kTLS socket; a remote TLS peer has no way to induce a disconnect. The TCP connection can be entirely loopback, so no network access is needed at all.\nAC:L - The sequence (attach TLS ULP, receive one record so the strparser latches `msg_ready` with a borrowed `frag_list`, disconnect, recvmsg) is fully under the attacker's control, single-threaded, and deterministic with no race to win. Heap grooming of the freed `skbuff_head` objects is standard and repeatable since the attacker can retry indefinitely.\nPR:L - `net/tls` contains no `capable()`/`ns_capable()` checks whatsoever, and `setsockopt(TCP_ULP,\"tls\")` plus `TLS_RX` crypto_info are available to any unprivileged user once the tls module is built in or resident. All steps are ordinary socket syscalls on a socket the attacker created.\nUI:N - The attacker performs every step themselves within a single process; no victim action, mount, or file open is involved.\nS:U - The corruption is confined to kernel memory managed by the same kernel security authority; there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - `skb_nsg()`/`skb_to_sgvec()` walk the anchor's dangling `frag_list` into freed `skbuff_head` slab objects, building a scatterlist from attacker-sprayable page pointers; the zero-copy AEAD then writes those kernel bytes into the user's buffer before the tag check fails, and since the attacker chose the RX key/IV they recover the plaintext — an arbitrary kernel memory read.\nI:H - This is a use-after-free: `tls_strp_msg_hold()` performs `skb_clone()` on freed skbs (refcount writes into reallocated slab memory) and queues clones that are later freed, giving heap corruption and arbitrary-free primitives usable for control-flow hijack.\nA:H - The immediate observable effect is the `WARN_ON` at net/tls/tls_strp.c:486 (a panic under `panic_on_warn`), and the subsequent dereference of freed skb metadata and wild page pointers reliably oopses the kernel." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tls/tls_main.c" ], "versions": [ { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "7bdcf5bc35ae59fc4a0fa23276e84b4d1534a3cf", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "ac91c6125468be720eafde9c973994cb45b61d44", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "f3ce4d3f874ab7919edca364c147ac735f9f1d04", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "2bcad8fefcecdd5f005d8c550b25d703c063c34a", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "9fcbca0f801580cbb583e9cb274e2c7fbe766ca6", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "c665bef891e8972e1d3ce5bbc0d42a373346a2c3", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "8513411ec321942bd3cfed53d5bb700665c67d86", "status": "affected", "versionType": "git" }, { "version": "3c4d7559159bfe1e3b94df3a657b2cda3a34e218", "lessThan": "5071a1e606b30c0c11278d3c6620cd6a24724cf6", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/tls/tls_main.c" ], "versions": [ { "version": "4.13", "status": "affected" }, { "version": "0", "lessThan": "4.13", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.237", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.181", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.135", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.88", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.24", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.12", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14.3", "lessThanOrEqual": "6.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "5.10.237" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "5.15.181" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.1.135" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.6.88" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.12.24" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.13.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.14.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.13", "versionEndExcluding": "6.15" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7bdcf5bc35ae59fc4a0fa23276e84b4d1534a3cf" }, { "url": "https://git.kernel.org/stable/c/ac91c6125468be720eafde9c973994cb45b61d44" }, { "url": "https://git.kernel.org/stable/c/f3ce4d3f874ab7919edca364c147ac735f9f1d04" }, { "url": "https://git.kernel.org/stable/c/2bcad8fefcecdd5f005d8c550b25d703c063c34a" }, { "url": "https://git.kernel.org/stable/c/9fcbca0f801580cbb583e9cb274e2c7fbe766ca6" }, { "url": "https://git.kernel.org/stable/c/c665bef891e8972e1d3ce5bbc0d42a373346a2c3" }, { "url": "https://git.kernel.org/stable/c/8513411ec321942bd3cfed53d5bb700665c67d86" }, { "url": "https://git.kernel.org/stable/c/5071a1e606b30c0c11278d3c6620cd6a24724cf6" } ], "title": "net: tls: explicitly disallow disconnect", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html" }, { "url": "http://www.openwall.com/lists/oss-security/2026/05/07/1" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2026-05-07T06:58:56.863Z" } } ] } }